Deciding the right path for shielding your credit report

In response to the breach, Equifax is now offering a year of free credit monitoring through its identity-theft prevention service, TrustedID Premier. The service gives you the option to freeze or lock your credit file with Equifax, but note that it won’t do the same for the other two major bureaus, Experian and TransUnion, or for the lesser-known Innovis.

What caught my attention was a note from Equifax that you can either lock or freeze your file, but you can’t do both. So what’s the difference?